For many Baltimoreans, it's not the holiday season until the lighting of the Washington Monument or a stroll down Hampden's 34th Street.

But for fans of chaotic, sweaty, dance-fueled scenes, it's not Christmastime until the Baltimore Bass Connection's Xmas Party.

Now in its ninth year, the annual concert is organized by creators Naeem Juwan, the 31-year-old rapper and Baltimore native better known as Spank Rock, and Emily "Rabbit" Wilkes McDonough, his 34-year-old road manager, who lives in Charles Village.

While it has grown to bethe type of event many music fans from the area (and beyond) circle on the calendar, the Xmas Party has always been a simple excuse to get a tight-knit group of friends — some of whom happen to be well-established musicians — together in one place.

"It hasn't changed much," McDonough said. "People have gotten more famous, so we don't get to see each other as much, so it's special to get everyone in the same room."

On Sunday, the Xmas Party takes over both floors of the Ottobar. While the various performers — including Braider, Big Mouth, Le1f, the Death Set and Spank Rock, along with numerous DJ sets — share few sonic similarities, they are united by the ability to rock crowds and jump-start parties.

"We created it to be something that was completely free of any sort of pretension or social 'cool' factors," Juwan said. "I can't even put it into words. It's consistent. It's the most pure party. We get giddy."

The Death Set's Johnny Siera, who called the event the "party of the year," compared it to another holiday.

If Siera, Juwan and McDonough sound sentimental, it's because the Xmas Party is more than just a concert to them. McDonough brought Siera and his Death Set partner, Beau Velasco, from Sydney, Australia, to Baltimore in 2005 after briefly signing the group to her RabbitFoot label. According to Juwan, they all "clicked so hard, 'band' became 'family' rapidly."

"The first few years, I'd call my parents and say, 'I'm bringing three of the weirdest people to Christmas dinner,' " McDonough said.

The quickly formed friendships led to musical collaborations and joint tours for Spank Rock and Death Set, further strengthening the bonds. "[They're] my oldest friends in America," Siera said.

In September 2009, the three friends lost Velasco to a drug overdose. It remains a delicate topic (only Juwan mentions Velasco), but because of it, the Xmas Party now probably holds greater significance for the old friends.

"After Beau's death, the intensity of the relationship that me, Rabbit, Johnny and Dan [Walker, another Death Set member] too, just became ..." Juwan began, before trailing off.

"Everyone deals with death their own way," he continued. "The absence of one person can make a unit even stronger. So now, playing shows with those guys means a lot more spiritually."

But more than anything, the yearly concert is a party proudly held in Baltimore, and the organizers would not have it any other way. Moving the event to Brooklyn, N.Y. (where Siera lives and co-owns the trendy Williamsburg bar The Flat), or Philadelphia (where Juwan moved 12 years ago) might be more practical, but the organizers worry it would lose its hard-to-describe specialness.

Juwan says had the party moved to New York, it "wouldn't stay this cool" and would have eventually "died out."

"I'm touring around playing festivals [throughout the year,] playing in front of thousands, and sometimes I hate it," Juwan said. "It feels like work. But every single year, when I come home to Baltimore [for the Xmas Party], it's not about anything but the music and having fun."

Come January, the three friends will get busy once again. Juwan wouldn't guarantee a new Spank Rock record for fear of jinxing himself, but he promises to release new material in 2013. Siera says the Death Set will release a new EP on Steve Aoki's Dim Mak Records. Besides being Juwan's road manager, McDonough books shows and conducts research for a lobbyist. These creative people will likely be busy for years to come, but they say they will continue to make time for their favorite event of the year.

"It's not about star status. It's about coming home," Juwan said. "It's like, 'We made it through another year. Let's party.' "

The Baltimore Bass Connection's Xmas Party 2012 is Sunday at the Ottobar, 2549 N. Howard St. in Charles Village. Spank Rock, The Death Set, Le1f and more will perform. Doors open at 8 p.m. 18+. Tickets are $15. Call 410-662-0069 or go to theottobar.com.